1. Field of the Invention
The invention generally relates to electronic devices. More particularly, the invention relates to a communications device and a transmitter included therein.
2. Background
There is an ever present need to reduce the power consumption of electronic devices. For example, a laptop computer or a wireless phone typically includes a battery to store and provide electrical energy for the operation of the electronic device. A user can operate the electronic device through the battery when no other source of electrical energy is available, or when the user wants to be mobile. Batteries, however, store only a limited amount of electrical energy, which is consumed by the electronic device.
The batteries, thus, have to be recharged after the electronic device has been used for a certain time. The time interval between two subsequent charging events is expressed as operating time. In wireless phones, for example, the operating time can further be divided into a stand-by time and a talk time.
The user of a wireless communications device such as a mobile unit or a cellular phone typically desires to have an operating time, particularly a talk time, which is as long as possible. Additionally, the user generally expects the wireless device to be as small and as light as possible. Because the operating time is dependent from the capacity and, thus, usually from the size of the battery, small size, low weight, long operating time of the wireless device are often contradictory expectations.
To fulfill these expectations, manufacturers seek to increase the capacity of the batteries without increasing the size and weight of the batteries. In addition, manufacturers of wireless devices have developed wireless devices which operate at lower voltages, for example 3.3 volts, to increase the stand-by time and the talk time.
One embodiment of the invention relates to a communications device which includes an amplifier module configured to amplify a signal. The amplifier module includes a parallel arrangement of amplifiers each designed for a specific power level range. A controllable switch selectively interconnects the power amplifiers. A controller in communication with the controllable switch selectively interconnects the power amplifiers based on the operating parameters of the communications device.
The transmit power of a communications device typically varies depending on the transmit conditions, the proximity of the communications device to a base station, etc. For example, a communications device may transmit at maximum power when poor transmit conditions exist. In many devices, the output power amplifier is optimized to generate the maximum power output.
If the transmit conditions are favorable or if a communications device is near a base station, the communications device often transmits at less than the maximum output power. Statistically speaking, a communications device typically sends most of its operational life transmitting at less than maximum power. For example, in a code division multiple access (CDMA) cellular phone, most of the time the phone operates below the maximum power output level within a range from about xe2x88x925 dBM (measured decibels referenced to a power of 1 milliwatt) to about +8 dBm. Accordingly, one embodiment of the invention increases the output power efficiency when an electronic device operates at a lower output power level.
Another embodiment of the invention relates to a wireless communications device comprising a modulator module that is configured to convert a baseband signal to a radio frequency signal. The wireless communications device also comprises an amplifier module which receives the radio signal and generates an amplified output signal.
The amplifier module comprises a first amplifier in communication with the radio frequency signal. The first amplifier is configured to generate a first amplified signal at increased efficiency in a first operational range.
The amplifier module also comprises a second amplifier in communication with the radio frequency signal. The second amplifier is arranged in parallel with the first amplifier. The second amplifier is configured to generate a second amplified signal at increased efficiency in a second operational range, wherein the second operational range is different than the first amplification range.
The amplifier module also comprises a third amplifier in communication with the radio frequency signal. The third amplifier is arranged in parallel with the first and second amplifiers. The third amplifier is configured to generate a third amplified signal at increased efficiency in a third operational range, wherein the third operational range is different than the first and second operational ranges.
The amplifier module further comprises a switch in communication with the first, second and third amplifiers. The switch is configured to select the first, second or third amplified signal as the amplified output signal.
The wireless communications device further comprises a control module in communication with the switch. The control module is configured to control the switch based on a desired operational level.
In one embodiment, for example, the first operational range is between 29 dBm and 19 dBm. The second operational range is between 20 dBm and 9 dBm. Third operational range between 10 dBm and xe2x88x921 dBm.
In another embodiment, the wireless communications device further comprises a selector that selectively enables the first, second or third amplifiers. In another embodiment, the selector receives a digital control value. In yet another embodiment, the control value identifies at least one of the first, second or third amplifiers. In an additional embodiment, the first amplifier farther comprises two serially-connected amplifiers.
Another embodiment of the invention relates to an amplification module comprising an input for receiving an input signal. The amplification module further comprising at least a first amplifier in communication with the input. The first amplifier is configured to amplify the input signal to generate a first amplified signal at increased efficiency within a first operational range.
The amplification module further comprising at least a second amplifier in communication with the input. The second amplifier is configured amplify the input signal to generate a second amplified signal at increased efficiency in a second operational range, wherein the second operational range is different than the first operational range.
The amplification module further comprising a switch in communication with the first and second amplifiers, the switch configured to output at least one of the first and second amplified signals as an amplified output signal.
In one embodiment, the first and second amplifiers are configured to be selectively activated. In another embodiment, the first amplifier operates in an operational range between 29 dBm and 19 dBm. The second amplifier operates in an operational range between 20 dBm and 9 dBm.
In one embodiment, the switch selects either the first or second amplified signal. In another embodiment, the switch combines the first and second amplified signals. In yet another embodiment, the amplification module further comprises a selector that is configured to at least enable or disable at least one of the first or second amplifiers.
In an additional embodiment, the amplification module further comprises at least a third amplifier in communication with the input. The third amplifier configured to amplify the input signal to generate a third amplified signal at increased efficiency in a third operational range, wherein the third operational range is different than the first and second operational ranges.
Another embodiment of the invention relates to an amplifier circuit comprising an input for receiving an input signal. The amplifier circuit further comprises at least a first amplifier in communication with the input. The first amplifier configured to amplify the input signal to generate a first amplified signal at increased efficiency within a first operational range.
The amplifier circuit further comprising at least a second amplifier in communication with the input. The second amplifier configured amplify the input signal to generate a second amplified signal at increased efficiency within a second operational range.
The amplifier circuit further comprising a selector in communication with the first and second amplifiers. The selector configured to enable at least one of the first and second amplifiers so as to generate an amplified output signal.
In one embodiment, the input signal is approximately 800 megahertz. In another embodiment, the input signal is approximately 1900 megahertz. In yet another embodiment, the amplified output signal is a wireless communications signal. In additional embodiment, the amplified output signal is a cellular communications signal.
In one embodiment, the amplified output signal is a Global System for Mobile Communications (GSM) communications signal. In another embodiment, the amplified output signal is a Personal Communications System (PCS) communications signal. In yet another embodiment, the amplified output signal is an Advanced Mobile Phone Systems (AMPS) communications signal.
Another embodiment of the invention relates to an amplifier circuit comprising a first means for amplifying an input signal to generate a first amplified signal at increased efficiency within a first operational range. The amplifier circuit further comprising a second means arranged generally parallel with the first means. The second means for amplifying the input signal to generate a second amplified signal at increased efficiency within a second operational range. The amplifier circuit further comprising a third means for selectively enabling the output of at least one of the first or second amplified signals.
In one embodiment, the amplifier circuit further comprises a fourth means for selectively enabling at least one of the first or second amplifiers. In another embodiment, the amplifier circuit further comprises a fifth means for controlling the fourth means. The fifth means enables at least one of the first and second amplifiers based on a desired operational range.
Another embodiment of the invention relates to a method of operating a wireless communications device comprising the acts of converting a baseband signal to a radio frequency signal and amplifying with a first amplifier, the radio frequency signal at increased efficiency in a first operational range to produce a first amplified signal. The method further comprising the act of amplifying with a second amplifier, the radio frequency signal at increased efficiency in a second operational range to produce a second amplified signal, wherein the second operational range is different than the first amplification range.
The method further comprising the act of amplifying with a third amplifier, the radio frequency signal at increased efficiency in a third operational range to produce a third amplified signal, wherein the third operational range is different than the first and second operational ranges. The method further comprising the act of selectively outputting based on a desired operational level, the first, second or third amplified signals as an amplified output signal.
In one embodiment, the first operational range is between 29 dBm and 19 dBm. The second operational range is between 20 dBm and 9 dBm. The third operational range is between 10 dBm and xe2x88x921 dBm.
In one embodiment, the method further comprises the act of selectively activating the first, second or third amplifier. In another embodiment, the method further comprises the act of processing a digital control value to selectively activate the first, second or third amplifier. In an additional embodiment, method further comprises the act of processing the first amplified signal with a fourth amplifier to generate a modified first amplified signal.
Another embodiment of the invention relates to method of amplifying an input signal comprising the acts of receiving an input signal and amplifying the input signal with a first amplifier to generate a first amplified signal at increased efficiency within a first operational range. The method further comprising the act of amplifying the input signal with a second amplifier to generate a second amplified signal at increased efficiency in a second operational range, wherein the second operational range is different than the first operational range.
The method further comprising the act of selectively enabling the output of at least one of the first and second amplified signals in response to a desired operational level.
In one embodiment, the method further comprises the act of selectively activating at least one of the first and second amplifiers. The first operational range is between 29 dBm and 19 dBm. The second operational range is between 20 dBm and 9 dBm.
In another embodiment, the act of selectively enabling selects either the first or second amplified signal. In yet another embodiment, the act of selectively enabling combines the first and second amplified signals.
Another embodiment of the invention relates to a method of amplifying an input signal comprising the act of amplifying with a first amplifier an input signal to generate a first amplified signal at increased efficiency within a first operational range. The method further comprising the act of amplifying with a second amplifier the input signal to generate a second amplified signal at increased efficiency within a second operational range. The method further comprising the act of selecting at least one of the first and second amplified signals so as to generate an amplified output signal.
In one embodiment, the input signal is approximately 800 megahertz. In another embodiment, the input signal is approximately 1900 megahertz. In yet another embodiment, the amplified output signal is a wireless communications signal. In an additional embodiment, the amplified output signal is a cellular communications signal.
In one embodiment, the amplified output signal is a GSM communications signal. In another embodiment, the amplified output signal is a PCS communications signal. In yet another embodiment, the amplified output signal is an AMPS communications signal.